Hi....I picked up a used gen 1 9 mm sub 2000. My first attempt firing it, I had a lot of fail to cycles. I took it home, took it apart an it was very dirty..I bought it used off Gun Broker an the guy must have fired it an put it away then sold it an shipped it. Cleaning the bolt carrier/tube cured it. I went to the range today an tried the 33 rd mag I got with it, a mag pro 17 I got off cheaper than dirt an it shot flawlessly with brass ammo. I threw a few alum cased rounds in a mag an they wouldn't eject. My old hi point 995 shot alum case no problem. My sig 938 an Beretta px4 shoot it fine too. I'll burn up the cheap aluminum stuff in my Beretta an not buy it again...I got a box of 250 Remington UMC off cheaper than dirt for $54 an it shot fine.